It's not a hard thing to come up with, but it's incredibly useful. Suppose you need to
iterate over each pair of values or indices in an array. Do you really want to
duplicate those nested loops in several places in your code? Of course not. Yet
another example of why code as data is such a powerful concept:
class Array
# define an iterator over each pair of indexes in an array
def each_pair_index
(0..(self.length-1)).each do |i|
((i+1)..(self.length-1 )).each do |j|
yield i, j
end
end
end
# define an iterator over each pair of values in an array for easy reuse
def each_pair
self.each_pair_index do |i, j|
yield self[i], self[j]
end
end
end
Now you can just call
array.each_pair { |a,b| do_something_with(a, b) }.
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that's great thanks
Posted by Dibi Store
on Dec 03, 2007 at 08:50 AM UTC - 5 hrs
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